alcohol has ruined more lives since forever than weed ever has. Weed makes people lazy and dumb at times, but it doesnt make them violent, and it doesnt make them angry.
I dont touch the stuff, but from what ive seen in person and general knowledge, id say paranoia is probably the worst side effect for some people which can be severe.
Weed only makes lazy people lazy. I learned how to play a few instruments on it in my younger days.